1. Field of Invention
The present invention relates to a telephone system that responds to a ring for a call received across an analog cable and to a signal that carries the telephone number of a caller, and in particular to a cordless telephone system that has a function for storing received data and for transferring data to a terminal registered with the telephone system.
2. Description of the Prior Art
Conventionally, when a telephone system connected to a cable receives CLI (Caller Line Identification) data, i.e., data for the telephone number of a caller, methods are employed whereby the telephone number of the caller is displayed on a display device (e.g., Japanese Unexamined Patent Publication No. Hei 4-304756), or whereby data is transmitted to a remote handset terminal of a telephone system and displayed.
For a cellular telephone, when its power is off, the system can store CLI data, which can be retrieved from the system, as needed.
In a conventional, second-generation cordless home telephone system, where the main terminal is connected to a cable and the main terminal and a plurality of remote handset terminals are connected by radio, when the remote handset terminals are within an area within transmission range of the main telephone terminal for home use, they receive data from the main terminal and are set to the wait state, but do not perform position registration. In a situation where there are no registered remote handset terminals within transmission range or where all of them are powered off, when CLI data is received by the main telephone terminal, since in the area there are no remote handset terminals than can respond, the received CLI data are merely stored in a storage circuit and are displayed on the display device of the main telephone terminal. The data that are stored will not be transferred to a remote handset terminal later, even when it is powered on or is relocated from a remote location and is again within transmission range.
In a case where a remote handset terminal that is the target for the reception of a selective call is out of range, a main telephone terminal for home use will notify all other remote handset terminals of the call and wait for their responses. Upon the receipt of the responses from the remote handset terminals, a communication state is established, and the CLI data that are received are erased without being reported to the remote handset terminal that was the target of the selective call. This operation is also performed for a conference call. Once one of the remote handset terminals is set in the communication state, CLI data is erased, even though there are other remote handset terminals that did not receive the CLI data.
Second-generation cordless telephones (PHSs: Personal Handy Phone Systems) have individual telephone numbers for use in public areas, and can receive CLI data individually. However, since for an area of in and adjacent to a home, a plurality of remote handset terminals share one telephone number, CLI data is not transmitted to a remote handset terminal that is not within transmission range when a call is received.
It is, therefore, an object of the present invention to provide a telephone system that stores CLI data, and that so manages remote handset terminals, that once a remote handset terminal that was not active in the vicinity of a home, when the CLI data was received, is again within transmission range and requests position registration, the telephone system notifies the remote handset terminal of the receipt of the call and transfers the CLI data that was received.
To achieve the above object, according to the present invention, when a home use main terminal for a second-generation cordless telephone receives a call and CLI data across an analog line, while a remote handset terminal is powered off or is outside the range of the home use main telephone terminal, the main terminal for home use stores the CLI data in its own memory, and transmits the CLI data to the remote handset terminal when the remote handset terminal is again active within range of the home use main terminal and requests position registration.
According to the present invention, a second-generation cordless telephone system, with which a plurality of remote handset terminals are registered, stores CLI data in its own memory upon receipt of a call and holds the CLI data while the registered remote handset terminals are not available. When a remote handset terminal that previously was not available is again active within range of the main terminal and requests position registration, the main terminal notifies the remote handset terminal of the receipt of the call and transmits the CLI data to the remote handset terminal and a call that was received while the remote handset terminal was not available. The remote handset terminal, after receiving the CLI data, displays the CLI data using a display circuit. In this fashion, when an alarm sound is generated in conjunction with the display of the CLI data, a call that was received while the remote handset terminal was not available can be easily identified.